The field of this invention is that of fuel systems for furnishing an air-fuel mixture to an internal combustion engine, and the invention relates more particularly to means for preventing freeze-up of a fuel supply or inlet means such as, idle screw or nozzle means or the like in a throttle body used in such a system during operation of the system.
In throttle body automotive fuel systems wherein idling speed fuel supply or fuel inlet nozzle means or the like are arranged in a throttle body for furnishing a selected fine stream of fuel into a throttle body for evaporating the fuel to form an air-fuel mixture to be furnished to an engine during idling operation of the engine, the cooling effect of expansion or evaporation of air and/or air-fuel mixtures in the throttle body means has a tendency to cause at least temporary freeze-up of such idle speed fuel inlet nozzle means with resulting failure of engine firing or loss of suitable engine driveability. Similar problems can also occur with freeze-up of air inlet nozzles or openings or the like in throttle bodies used in throttle body fuel injection systems or in direct port fuel injection systems and the like. Such freeze-ups tend to occur particularly during the occurrence of selected atmospheric conditions. It would be desirable if heat could be furnished to throttle bodies of such systems promptly after initiation of engine operation to prevent such freeze-ups.